SpreadsheetWebApp (P2J - Progress 4GL to Java Conversion and Runtime)

java.lang.Object
- com.goldencode.p2j.main.SpreadsheetWebApp

```
public class SpreadsheetWebApp
extends java.lang.Object
```
Represents a web application for managing and interacting with spreadsheets through a web interface. This class initializes and manages the lifecycle of the web application including starting, stopping, and handling of web contexts for spreadsheet widgets. It utilizes Jetty for web server functionality and is designed to be accessed as a singleton instance.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`SpreadsheetWebApp.Context` The Context class represents the context within which a spreadsheet widget operates.
`static class`	`SpreadsheetWebApp.SecurityContextDispatcher` The class provides a mechanism to execute runnables asynchronously in a separate thread associated with the related security context.

Field Summary

Fields
Modifier and Type	Field and Description
`private java.util.Set<java.lang.Integer>`	`activeWidgets` The set of active spreadsheet widget ids
`private static java.lang.String`	`CONTEXT_PATH` The static part of context path
`private static java.util.Map<java.lang.Integer,SpreadsheetWebApp.Context>`	`contexts` A map that stores the Spreadsheet application contexts.
`private static java.lang.ThreadLocal<java.lang.String>`	`currentRequestOrigURI` Thread-local storage for current request
`private static SpreadsheetWebApp`	`instance` Singleton instance of the SpreadsheetWebApp class.
`private static java.util.concurrent.atomic.AtomicInteger`	`lastContextId` Represents an atomic integer that is used to generate a unique context ID.
`private static CentralLogger`	`LOG` Logger
`private org.eclipse.jetty.webapp.WebAppContext`	`webApp` WebAppContext for managing the web application's servlet context.

Constructor Summary

Constructors
Constructor and Description

SpreadsheetWebApp()

Constructors
Constructor and Description
`SpreadsheetWebApp()`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static SpreadsheetWebApp.Context`	`getContext()` Returns the spreadsheet web app context belonging to the current HTTP request (i.e.
`static SpreadsheetWebApp.Context`	`getContext(int contextId)` Returns the spreadsheet web app context associated with the specified contextId.
`static int`	`getContextId()` Returns the ID if the spreadsheet web app context belonging to the current HTTP request (i.e.
`static int`	`getContextId(java.lang.String path)` Retrieves the ID of the spreadsheet web app context from the supplied path.
`static java.lang.String`	`getCurrentRequestOrigURI()` Returns the current request URI
`static SheetEventHandler`	`getEventHandler()` Returns the SheetEventHandler instance belonging to the current HTTP request (i.e.
`static SpreadsheetWebApp`	`getInstance()` Retrieves the singleton instance of the SpreadsheetWebApp.
`private static <T> T`	`getPrivateFieldValue(java.lang.Class clazz, java.lang.Object targetObject, java.lang.String fieldName)` Returns the value of a private field in the given object without throwing checked exceptions.
`private java.io.File`	`getWARPath()` Returns the path of the spreadsheet backed war file.
`static int`	`getWidgetId()` Returns the spreadsheet widget ID belonging to the current HTTP request (i.e.
`org.eclipse.jetty.server.Handler`	`init()` Initializes the web application.
`boolean`	`isStarted(int widgetId)` Checks if the web application is started for a specific widget ID.
`static int`	`onSpreadsheetWidgetCreated(SpreadsheetWidget widget, SheetEventHandler eventHandler)` This method is called when a SpreadsheetWidget is created.
`static void`	`onSpreadsheetWidgetDeleted(SpreadsheetWidget widget)` Removes the context associated with a deleted SpreadsheetWidget.
`static void`	`postServerEvent(int contextId, java.lang.Runnable run)` The method invokes `ClientExports.postServerEvent(ServerEvent)` asynchronously in a thread associated with the security context related to the supplied spreadsheet web app context.
`static void`	`postServerEvent(SpreadsheetWebApp.Context context, java.lang.Runnable run)` The method invokes `ClientExports.postServerEvent(ServerEvent)` asynchronously in a thread associated with the security context related to the supplied spreadsheet web app context.
`java.lang.String`	`start(int widgetId)` Starts the web application for a specific spreadsheet widget identified by its widget ID.
`void`	`stop(int widgetId)` Stops the web application for a specific widget ID.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - LOG
```
private static final CentralLogger LOG
```
    Logger
  - instance
```
private static final SpreadsheetWebApp instance
```
    Singleton instance of the SpreadsheetWebApp class.
  - CONTEXT_PATH
```
private static final java.lang.String CONTEXT_PATH
```
    The static part of context path
    
    See Also:
    
    Constant Field Values
  - webApp
```
private org.eclipse.jetty.webapp.WebAppContext webApp
```
    WebAppContext for managing the web application's servlet context.
  - activeWidgets
```
private java.util.Set<java.lang.Integer> activeWidgets
```
    The set of active spreadsheet widget ids
  - currentRequestOrigURI
```
private static java.lang.ThreadLocal<java.lang.String> currentRequestOrigURI
```
    Thread-local storage for current request
  - lastContextId
```
private static java.util.concurrent.atomic.AtomicInteger lastContextId
```
    Represents an atomic integer that is used to generate a unique context ID.
  - contexts
```
private static java.util.Map<java.lang.Integer,SpreadsheetWebApp.Context> contexts
```
    A map that stores the Spreadsheet application contexts. The map is thread-safe and allows concurrent access.
- Constructor Detail
  - SpreadsheetWebApp
```
public SpreadsheetWebApp()
```
- Method Detail
  - getInstance
```
public static SpreadsheetWebApp getInstance()
```
    Retrieves the singleton instance of the SpreadsheetWebApp.
    
    Returns:
    
    The singleton instance of SpreadsheetWebApp.
  - getCurrentRequestOrigURI
```
public static java.lang.String getCurrentRequestOrigURI()
```
    Returns the current request URI
    
    Returns:
    
    See above.
  - init
```
public org.eclipse.jetty.server.Handler init()
```
    Initializes the web application.
  - start
```
public java.lang.String start(int widgetId)
```
    Starts the web application for a specific spreadsheet widget identified by its widget ID. This method sets the context path and starts the web application context. If the application fails to start, it logs the error and returns null.
    
    Parameters:
    
    widgetId - The ID of the widget for which the web application is to be started.
    
    Returns:
    
    The path to the started web context or null if the application failed to start.
  - isStarted
```
public boolean isStarted(int widgetId)
```
    Checks if the web application is started for a specific widget ID.
    
    Parameters:
    
    widgetId - The ID of the widget to check.
    
    Returns:
    
    true if the web application is started, false otherwise.
  - stop
```
public void stop(int widgetId)
```
    Stops the web application for a specific widget ID. If the application is not running, this method does nothing.
    
    Parameters:
    
    widgetId - The ID of the widget for which the web application is to be stopped.
  - onSpreadsheetWidgetCreated
```
public static int onSpreadsheetWidgetCreated(SpreadsheetWidget widget,
                                             SheetEventHandler eventHandler)
```
    This method is called when a SpreadsheetWidget is created. It is responsible for creating a context, assigning necessary values to it, initializing the dispatcher, setting the context ID in the SpreadsheetConfig, and adding the context to the map of contexts.
    
    Parameters:
    
    widget - The SpreadsheetWidget that was created.
    
    eventHandler - The SheetEventHandler that will handle events for the SpreadsheetWidget.
    
    Returns:
    
    The ID of the created context.
  - onSpreadsheetWidgetDeleted
```
public static void onSpreadsheetWidgetDeleted(SpreadsheetWidget widget)
```
    Removes the context associated with a deleted SpreadsheetWidget.
    
    Parameters:
    
    widget - The SpreadsheetWidget that was deleted.
  - getWidgetId
```
public static int getWidgetId()
```
    Returns the spreadsheet widget ID belonging to the current HTTP request (i.e. loading the spreadsheet web component from the JS client, handling an event triggered in the spreadsheet web component, etc.).
    
    Returns:
    
    See above.
  - getEventHandler
```
public static SheetEventHandler getEventHandler()
```
    Returns the SheetEventHandler instance belonging to the current HTTP request (i.e. loading the spreadsheet web component from the JS client, handling an event triggered in the spreadsheet web component, etc.).
    
    Returns:
    
    See above.
  - getContext
```
public static SpreadsheetWebApp.Context getContext()
```
    Returns the spreadsheet web app context belonging to the current HTTP request (i.e. loading the spreadsheet web component from the JS client, handling an event triggered in the spreadsheet web component, etc.).
    
    Returns:
    
    See above.
  - getContextId
```
public static int getContextId()
```
    Returns the ID if the spreadsheet web app context belonging to the current HTTP request (i.e. loading the spreadsheet web component from the JS client, handling an event triggered in the spreadsheet web component, etc.).
    
    Returns:
    
    See above.
  - getContext
```
public static SpreadsheetWebApp.Context getContext(int contextId)
```
    Returns the spreadsheet web app context associated with the specified contextId.
    
    Parameters:
    
    contextId - The identifier of the context object to retrieve.
    
    Returns:
    
    The Context object associated with the specified contextId.
  - getContextId
```
public static int getContextId(java.lang.String path)
```
    Retrieves the ID of the spreadsheet web app context from the supplied path. The path is expected to have the following form: /sheet/[context ID]/whatever/subpath/components.
    
    Parameters:
    
    path - The path of the current HTTP request.
    
    Returns:
    
    The ID of the spreadsheet web app context, or -1 if the ID cannot be determined.
  - postServerEvent
```
public static void postServerEvent(int contextId,
                                   java.lang.Runnable run)
```
    The method invokes ClientExports.postServerEvent(ServerEvent) asynchronously in a thread associated with the security context related to the supplied spreadsheet web app context.
    
    Parameters:
    
    contextId - ID representing a valid spreadsheet web app context.
    
    run - The code to be executed when the server event is handled on the server.
  - postServerEvent
```
public static void postServerEvent(SpreadsheetWebApp.Context context,
                                   java.lang.Runnable run)
```
    The method invokes ClientExports.postServerEvent(ServerEvent) asynchronously in a thread associated with the security context related to the supplied spreadsheet web app context.
    
    Parameters:
    
    context - A valid spreadsheet web app context.
    
    run - The code to be executed when the server event is handled on the server.
  - getPrivateFieldValue
```
private static <T> T getPrivateFieldValue(java.lang.Class clazz,
                                          java.lang.Object targetObject,
                                          java.lang.String fieldName)
```
    Returns the value of a private field in the given object without throwing checked exceptions.
    
    Parameters:
    
    clazz - the class whose private field is to be read
    
    targetObject - the object whose private field is to be read
    
    fieldName - the name of the private field to be read
  - getWARPath
```
private java.io.File getWARPath()
```
    Returns the path of the spreadsheet backed war file.
    
    Returns:
    
    See above.

Class SpreadsheetWebApp

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

LOG

instance

CONTEXT_PATH

webApp

activeWidgets

currentRequestOrigURI

lastContextId

contexts

Constructor Detail

SpreadsheetWebApp

Method Detail

getInstance

getCurrentRequestOrigURI

init

start

isStarted

stop

onSpreadsheetWidgetCreated

onSpreadsheetWidgetDeleted

getWidgetId

getEventHandler

getContext

getContextId

getContext

getContextId

postServerEvent

postServerEvent

getPrivateFieldValue

getWARPath